1. Field of the Invention
The present invention generally relates to an ion generator and a hairbrush utilizing such ion generator.
2. Description of the Prior Art
The conventional ion generator A generally includes a needle electrode 101 and a ring-shaped ground electrode 102, both of which are accommodated within a tubular body 107, for example, a cylindrical body made of an electrically insulating material. As shown in FIGS. 12A to 12C, the ground electrode 102 within the tubular body 107 is so positioned as to occupy a position coaxial with an imaginary extension M of the longitudinal axis of the needle electrode 101 for generating ions by effecting a corona discharge in the air. In an alternative arrangement not shown, the ground electrode 102 similar in shape to a flat rectangular plate is disposed forwardly and diagonally upwardly of the needle electrode. In either case, there has been a problem in that most of the ions generated by the corona discharge propagate towards the ground electrode 102 along a direction in which lines of electric force develops from the needle electrode 101 to the ground electrode 102 and, therefore, unless a propulsive force such as, for example, wind is applied externally to the ions, the ions are unable to emerge outwardly from a blowoff port 103 at one end of the tubular body 107 remote from the needle electrode 101.
FIGS. 13A and 13B illustrates the lines of electric force developed where the ground electrode 102 of a ring shape is disposed coaxial with the imaginary extension M of the longitudinal axis of the needle electrode 101 for generating ions by effecting a corona discharge in the air. As shown therein, the lines of electric force extend from the needle electrode 101 towards the ring-shaped ground electrode 102 and, accordingly, the ions do not emerge outwardly from the blowoff port 103, but travel in most quantity towards the ground electrode 102. Thus, unless a propulsive force such as, for example, wind is applied externally to the ions, the ions are unable to emerge outwardly from a blowoff port 103 at one end of the tubular body 107 remote from the needle electrode 101.
Another conventional ion generator shown in FIG. 30 includes a needle electrode 101 and a ground electrode 102, both accommodated within a tubular casing 109, and a high voltage generator 5 disposed within a housing 110 together with the casing 109. The housing 110 is a molded product or is made of metal. In this arrangement, there has been a similar problem in that most of the ions generated by the corona discharge taking place between the needle electrode 101 and the ground electrode 102 tend to deposit and be electrostatically charged on a portion of the housing 110, in the form of the molded product or made of metal, around the blowoff port 103 and do not therefore emerge outwardly from the blowoff port 103 as shown in FIG. 31. Even the ion generator shown in FIG. 30, unless a propulsive force such as, for example, wind is applied externally to the ions, the ions are unable to emerge outwardly from the blowoff port 103 at one end of the tubular casing 109 remote from the needle electrode 101.
The Japanese Laid-open Patent Publication No. 11-191478, for example, discloses the ion generator that does not make use of any ground electrode. According to this publication, the ion blowoff port is electrically connected with an alternating current source through a resistor to thereby avoid a charge build up at the blowoff port. However, in this prior art ion generator in which no ground electrode is employed and, instead, the ion blowoff port is connected with the alternating current source through the resistor, the absence of the ground electrode does not make it possible to form an electric field that is necessary to generate ions outside and, therefore, no ion can be generated stably.
As an alternative embodiment, the above referenced patent publication also discloses the ion blowoff port connected direct with the ground only where the blowoff port has a grille or a grid made of a semiconductor material.
The use of the ion generator in a hairbrush is contemplated so that the user of the hairbrush can take care of his or her hair while ions generated from the ion generator are applied to the hair. The inventors of the present invention have suggested the hairbrush of a structure shown in FIGS. 32 to 34, reference to which will now be made.
As best shown in FIGS. 32 and 33, the hairbrush B includes a tubular handle and a brush head at one end of the handle. The brush head has a generally oval brush base 112 on which a multiplicity of bristles 113 are fixedly planted, or otherwise formed integrally therewith by means of an injection molding technique. The brush base 112 also has a center hole 112a aligned with the ion blowoff port 103 of the ion generator A, encased within the brush head, so that ions generated from the ion generator A can emerge outwardly of the brush head through the center hole 112a by way of the ion blowoff port 103 to deposit on the user's hair during the hair brushing.
It has, however, been found that the hairbrush of the structure shown in FIGS. 32 to 34 and having the ion generator built therein has a problem in that because of the presence of the bristles 13 in the vicinity of the ion blowoff port 103 and around the center hole 112a as shown therein, some of the ions so generated from the ion generator A tend to deposit on some of the bristles 113, causing the bristles 113 to be electrostatically charged to such an extent as to adversely affect the electric field therearound with the consequence that the ions do not emerge outwardly of the brush head sufficiently.
More specifically, when minus ions, that is, anions are generated from the ion generator A, the anions so generated tend to deposit on some of the bristles 113 adjacent the center hole 112a, causing the bristles 113 to be charged to a negative polarity. Once the bristles 113 adjacent the center hole 112a are charged to the negative polarity, it has been found that the negative charge acts to repel the anions and, therefore, the ions cannot emerge outwardly of the brush head.
Conversely, if plus ions, that is, cations are generated from the ion generator A, the cations so generated tend to deposit on some of the bristles 113 adjacent the center hole 112a, causing the bristles 113 to be charged to a positive polarity. Once the bristles 113 adjacent the center hole 112a are charged to the positive polarity, it has also been found that the positive charge acts to repel the cations and, therefore, the ions cannot emerge outwardly of the brush head.
Because of the reasons discussed above, even though the ion generator A is built in the hairbrush B, the ions generated from the ion generator A can not be continually blown off to the outside of the brush head so as to travel towards a site desired to be treated with ions.